Fire extinguisher



Oct. 16,1951

Filed Oct. 26, 1948 T. A. HENSHAW FIRE EXTINGUISHER 2 SHEETS-SHEET 2 i n i i i I l E i INVENTOR. $40M [2 M BYW M Patented Oct. 16, 1951 FIRE EXTINGUISHER Thomas A. Henshaw, Elland, England, assignor to Nu-Swift, Limited, Elland, England Application October 26, 1948, Serial No. 56,649 In Great Britain October 28, 1947 6 Claims.

The invention relates to fire extinguishers of the kind which are operated by means of a sealed vessel containing either a compressed or liquefied gas or a suitable gas-generating cartridge, the invention being designed for application to extinguishers of this kind in which it is desired to keep a liquid orsemi-liquid or a solid or powder-form substance or mixture of substances separate, until the time of operation, from water or other liquid in an outer container 'of.the extinguisher. The purpose of the invention is to seal hermetically such substance or mixture of substances in such a manner as to prevent deterioration or corrosion or premature chemical interaction, and at the time of operation to cause such substance or mixture of substances to be forcibly projected into and intimately mixed with the water or other liquid in the outer container immediately prior to any material discharge of the contents of the extinguisher.

The invention has been designed for application more particularly to fire extinguishers of the kind in which foam is employed as the extinguishing medium, but as will be apparent from the following description it is applicable to extinguishers of any other type in which it is desired to keep a chemical or other substance or mixture of substances separate, until the time.

of operation, from the water or other liquid carried in the outer container and thereby prevent deterioration, corrosion or premature chemical interaction.

In the known constructions of fire extinguishers in which the extinguishing meduim is chemical foam the mixing of the foam-producing agent when released from an inner container in the extinguisher is effected primarily by gravity and is completed by shaking the extinguisher.

In the known extinguishers in which pre-mixed solutions are employed, such solutions can deteriorate or. cause corrosion of the outer container, which is disadvantageous as the latter is subjected to considerable internal pressure when the extinguisher is operated.

The present invention, which is designed to overcome the objections just referred to, is characterised, and is differentiated from all previously-known constructions, in that, instead of a foam-producing or other agent being pre-mixed with the water or other liquid in an outer container, it is carried in a hermetically-sealed container within or the gas-generating cartridge in communication with the interior of the outer container in such a manner that whengas is 2 released from a sealed container or a gas generating cartridge, it first functions to unseal the container housing the foam-producing or other agent and so to act upon such agent that the latter is projected or driven forcibly into the water or other liquid in the outer container in such'a manner that it becomes very rapidly and intimately admixed therewith, the pressure of the released or generated gas then continuing to function to cause expulsion of the admixed extinguishing medium from the extinguisher.

In the known extinguishers in which pre-mixed solutions are employed, such solutions can de-' teriorate or cause corrosion of the outer container, which is disadvantageous as the latter is subjected to considerable internal pressure when the extinguisher is operated.

In one convenient embodiment of the invention a charge of appropriately concentrated liquid foaming-agent is carried between two frangible diaphragms or equivalent easilyrupturable sealing members which are arranged to close the passage-Way through a tubular member depending from the neck of the outer container, and the container for the compressed gas or gasgenerating cartridge is disposed between the upper frangible diaphragm or sealing member and a closing cap for the outer container. The dimensions of the tubular member and the distance it extends down towards the bottom of the outer container will be such as may be found to give the best results.

It may be found desirable to control or regulate the rate of ejection of the foaming agent into the liquid medium. This may be efiected in various ways such as by controlling the rate of action of the gas charge upon the sealing members and foaming-agent, or by regulating the size or area of the sealing members for the charge of foaming-agent, or by regulating the viscosity of the foaming-agent or by regulating the area of. the orifice or orifices through which the foaming agent is ejected into the liquid, or by a combination of some of these means.

In an alternative embodiment of the invention the usual removable or separate closing head for the outer container may be dispensed with and a cartridge carrying the gas or the gas-generating charge, or a container or holder for such a cartridge may itself form a readily detachable closurefor an orifice in the outer container and be so proportioned as to fill completely such an orifice which may be of sufficient size to allow of rapid-filling and easy inspection. The cartridgeor its holder is capable of sufficient moveanther"? ment under manually-applied pressure to enable a sealing disc or cap carried by its lower end to be pierced or struck by a stationary piercer or striker located between the said sealing disc and a rupturable sealing member closing the upper end of a chamber or compartment containing a foaming agent or other liquid or substance, the lower end of such chamber or compartment, exposed to the liquid in the outer container, having also a rupturable sealing member designed, when pressure gas from the gas cartridge is permitted to rupture the upper sealing member, to itself be ruptured by the pressure exerted against it and thus permit of expulsibn of the foaming agent or other liquid or substance into the liquid in the outer charmer. The cartridge or its holder maintains or constitutes an efiective seal for the outer container just described the cartridge for the gas or the gas generating o'r liberating charge may have its sealing disc or cap at its upper end, the lower end of the cartridge resting upon the lower part of a holder for the cartridge and the piercer or striker being carried by the inner side of an upper half of the holder which is capable of suit.- cient movement, against the action of a spring confined between itself and a shoulder on the cartridge to permit the p'iercer or striker to pierce the seal or to strike the cap of the cartridge. Further, instead of the piercer or striker being carried fixedly by the upper part of the cartridge holder, it may be slidable through an opening in such upper part and be operable by means of an external strike knob. Appropriate means may be provided to guard against accidental movement of the upper part of the holder.

Figs. 1 and 2 of the accompanying drawings show, respectively, in sectional elevation, two alternative embodiments of the invention which though good and practicable, are only shown by way of illustration and are capable of modifica tion without departing from. the spirit and scope or the invention; 7 Figs. 3, 4 and 5 illustrate details hereinafter referred to.

Referring specifically to Fig. 1, (1. represents the upper part of acontainer, herein referred to as the outer container, adapted to receive liduid and provided with the usual dip pipe at and discharge hose and nozzle 01. to permit of expulsion of the liquid when pressure is "applied to its upper surface. At b there is shown a tubular memher or inner container, the lower end of which is closed by an easily-rupturable diaphragm b. The container 1) depends from and is carried by a ring 0 flanged outwardly at c to rest upon a shoulder 03 on a neck ring (1 surrounding an orifice in the top of the outer container at.

A vessel or cartridge 9 for a compressed gas charge is disposed between a diaphragm i in the container 2) and a closing cover h for the outer container a, said gas cartridge being shown as fitting into an internally-threaded opening in a central boss 0 of thering c which carries the inner container b.

The closing cover h carries, in known manner, a plunger it provided with a piercer h'z adapted, on inward movement of the plunger against the pressure of a spring M, to rupture a sealing disc g closing the gas cartridge g.

It will be apparent that, on rupture of the seal of the gas cartridge, the released gas will fill the space above the diaphragm f, and as the latter is designed to give way under a relatively low pressure, the pressure of the released gas ruptures the diaphragm and acts upon the foamproducing or other agent in the inner container "0, causing it to burst through the diaphragm I) normally closing the lower end of said container. The rupture of the diaphragm b causes the foam-producing or other agent to be projected very rapidly from the inner container into, and intimately admixed with, the liquid in the outer container, The pressure then exerted by the released gas upon the upper surface of the liquid medium in the outer container causes expulsion of -the medium in the usual and well-known way throughi the dip tube and discharge nozzle.

If preferred, instead of the container (2 being supported as shown by a ring such as c it may be carried by the head or closing cover h so as to be removable therewith.

It may be found desirable to control or regulate the rate of ejection of the foam-producing or other agentfrom the inner container in into the liquid in the outercbntainer a. This may con veniently be done by arranging that instead of the whole area of the diaphra'gms b and I being easily rupturable, the said diaphragms are generally strohg enough to resist the pressure of the released gas, but are provided with relatively thin portions as indicated at i inth'e detail Fig. 3. Alternatively, the regulation or control of the rate of ejectibn might be efited by controlling the rate of action of the gas charge upon the foam-producing or other agent and thus upon the'rupturable diaphragrris closing the inner containe-r, or it might be effected by regulating the viscosity of the foam-producing or other agent in the inner container, or aconibination of some or all of the contro means mentioned, or of their equivalents might be employed.

In the arrangement or embodiment shown in Fig. 2, the use of a closing cap such as h "with its associated parts cassettes with. Instead, the gas cartridge 0 is inverted and its neck e is slid able in a guide 7" surrounding "a fixed piercer '7', a coiled spring 1c nbrinally holding the sealing disc of the g'a's cartridge nearer the piercer.

A suitable cover or shield in, enclosing the up per end of the gas cartridge '9, is provided with radially-extending lugs m adapted to engage with bayonet slots 71' in a neck ring 'n of the outer container 1. As will'be seen from the drawing, the cover or shield is adapted to abut upon the upper end of the gas cartridge soth'at downward pressure upfq'n the member will depress the cartridgea d cause its setting disc to be ru tured by triepi o'er fa. It will also be seen that the slots it a sumcinuy deepto -permit ofthe necessary (1' ward niove mentof the'c'over m to efi'e'ct releas of'th'e gas from the cartridge. 7 As'will be seen, the iuwe'r' ud of the cover m is slidable between the 'g matter 1t, and the member 1' a suitable packing is being provided to prevent leakage. Apfibpriate means may be provided to guard against accidental depression of the cover 172. 4 y I Pins 25, projecting from the member 7' above an internal flange on the lower end of the cover m enable the inner container 1) to be infserted and withdrawn along with theassembl'y or the gas cartridge and cbver, the flange he being appropriately interrupted at intervals so that the over m e rembv'eu and abplie'd without disturbing inner container b. An external flange "1' on the member '9 is adapted to rest upon an internal flange n on the member 12. the action of the spring is serving to hold th said flange 7'? down on to the flange n pi As previously mentioned, the cartridge g may have its neck g and sealing disc g at its upper end, the lower end of the cartridge resting upon the perforated base of the part i and the piercer 9' may be carried by the inside of the cover m or by a plunger extending slidably through the cover and operable by an external strike knob.

An advantage of prime importance presented by the invention is that the hermetic sealing of the foam-producing or other agent, until it is required for use, obviates any bacteriological contamination or deleterious action from the atmosphere or otherwise. Moreover, if the agent concerned is of such a character that if admixed with the liquid in the outer container it might set up corrosion of the outer container, this is completely avoided, since the inner container can be made of a suitable non-corrosive substance. A further advantage is that the Whole charge assembly can be very quickly removed and replaced when re-charging or inspection of the extinguisher is necessary.

Whilst the particular embodiments of the invention described and illustrated are good and practical, it is to be understood that they are only given by way of example, as it will be obvious that various alternatives or variations in detail are possible within the scope of the invention, the essential and characteristic features of which are the hermetic sealing of a charge of foam-producing or other agent within the outer container of a fire extinguisher and the utilisation of a compressed or liquified gas or gas generating or liberating cartridge to effect the release of the charge of foam-producing or other agent and its dispersal into the liquid charge of the extinguisher, and the discharge of such liquid from the extinguisher.

Instead of employing frangible diaphragms such as b and f, or frangible portions of diaphragms such as shown at i in Fig. 3, the sealing of the foam-producing or other agent container may be effected by detachable diaphragms or members such as 9' in Fig. 4, suitably held in position and capable of being detached by the pressure of the released gas. In a still further arrangement, flexible diaphragms such as 70", Fig.

4, may be employed, the peripheral portions of such diaphragms being clamped between ring members is and k and being capable when the diaphragm is flexed as shown in dotted lines by the action of the released gas to be withdrawn from between the clamping rings.

While I have mentioned the cartridge, bottle or vessel as containing either a charge of compressed gas or a gas generating charge, the net result is the same when gas is liberated from the cartridge. The gas thus liberated causes the foaming liquid in the inner container to be released therefrom and become directly intermingled with the reaction liquid in the outer or main container, the resulting mixture promptly foaming up and beginning to escape through the outlet port from said container.

Thus, the gas from the cartridge, whether simply escaping from a compressed or liquifled charge of gas or derived from a gas generating charge, may be expressed broadly as gas liberated from this cartridge and forming a primary driving fluid. The foam producing fluid in the inner container is thus a secondary driven fluid, while the foam resulting from the admixture of the latter fluid with the reacting liquid in said outer main container may be considered the ultimate driven fluid. The operation thus virtually pro-. ceeds through two stages, the first stage being the liberation of the driving gas and the second stage the mixing of the reacting fluids with-resulting propulsion and ejection of the foam as already intimated.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A fire extinguisher including an outer main container for a liquid, having a discharge port and a charging opening; removable closure means for closing said opening; a sealed first inner container disposed within the main container and containing a charge capable of liberating driving gas under pressure from the inner container when the latter is opened; a penetrable seal upon the latter; a piercing member on said removable closure means for breaking the penetrable seal on said inner container upon said penetrable seal coming into forcible contact with said piercing member; a second inner container for separately containing a foam producing or other agent connected to and enveloping at least a' portion of the first inner container in such fashion as to form a removable unit therewith; a frangible closing diaphragm sealing one portion of the second inner container from said first inner container; and a second frangible closing diaphragm in another portion of said second inner container spaced apart from the first mentioned closing diaphragm in such position as to be exposed to the interior of said main container and together with said first closing diaphragm enclosing said foam producing or other agent, with the latter foam producing or other agent disposed in the path of driving gas liberated from said first inner container so as to cause said foam producing agent to be driven into intimate mixture with the liquid in said main container when said pene trable portion of said first inner container is broken by said piercing member.

2. A fire extinguisher comprising, in combination, a first vessel having a discharge port and a charging opening; closure means removably mounted on said opening of said first vessel so as to close said vessel; a second vessel connected to said closure means and extending into said first vessel, said second vessel having a frangible diaphragm forming a part thereof, whereby said second vessel is placed in communication with said first vessel when said frangible diaphragm is broken; a sealed gas cartridge mounted in said second vessel; and means for opening said gas cartridge, whereby the pressure of the gas released by said cartridge upon the opening thereof will force any liquid or powder located in said second vessel against said frangible diaphragm so as to break said diaphragm by said gas pressure and force said liquid or powder out of said second vessel into any liquid contained in said first vessel and will force the mixture of the materials of said two vessels out through said discharge port.

3. A fire extinguisher comprising, in combination, a first vessel having a discharge port and a charging opening; closure means removably mounted on said opening of said first vessel so as to close said vessel; a second vessel connected to said closure means, so as to be removable therewith, and extending into said first vessel, said second vessel having a frangible diaphragm forming a part thereof, whereby said second vessel is placed in communication with said first 7 tvheri safii -'-'f ra rigible dia?ph man is "broken; af'sealed gas "cartridge in-hunted "in said second vessel and-means for opening said gascartridge, whereby the-pressure-of thegas released by said cartridge "upon the opening thereof 'will force any'liquid or powder locatedinsaidsecond'vess'el against said frangible diaphragm so as to break said diaphragm by said gas pressure and force said liquid or powder out of saidsecond vessel into any liquid contained in said first vessel and will force the mixture of the materials -of said two vessels out through said discharge port.

4. A fire -extinguisher con'iprising, in combination, fa first vessel --having a discharge banana a charging opening; closure means removably mounted on said opening -of said first vessel so as'to close said vessel; a second vessel connected to "said closure means, so as to be removable therewith, and extending into said first vessel, sa'id'second vessel having a frangible-diaphragm forming a part thereof, whereby said second vessel placed in communication with said first vessel when said frangible diaphragm is broken; a sealed container of gas under pressure mounted in said second vessel; 'and means for opening said container of gas under pressure, whereby the pressure of the gas released by said container upon the opening thereof will force any-liquid orpowder located in said'second vessel against said frangible diaphragm 'so as to break said diaphragm by said'gas pressure and force said liquid or powder out of said second vessel into any liquid contained in said first vessel and will force the mixture of the materials of said two "vessels out through said discharge port.

5. A fireextinguisher comprising, in'combination, a first vessel having a discharge port and a charging opening; closure means removably mounted on said opening of said first vessel so as tojclose said vessel; a second vessel connected to said closure means, so as to be removable therewith, and extending into said'first vessel, said second vessel having a frangible diaphragm forming a part thereof, wherebysaid second vessel is placed in communication with said first vessel when said frangible diaphragm is broken; a sealed container of gas under pressure mounted in said second vessel; a liquid foaming agent located in said second vessel; a second liquid located in said first vessel and adapted to be placed in condition for forming a foam upon contacting the atmosphere when said liquid foaming agent is mixed therewith; and means fer opening said "contai-iierof gas under-pressure; whereby the pressure of the-gas released by said container upon the opening thereof will force said roaming agem against said frangible diaphragm-so as-to break said diaphragm by said gas eressure am force said foaming agent out of said second vessel -into said second liquid "and will forcethe mixture of the'liquids of said two vessels out-through said discharge port.

6.-- A- fire extinguisher comprising, in combination, a first vessel having "a discharge por't and a charging opening; closure --means removably mounted on said opening of said first vesselso as to erase said vessel; a tubular second vessel havingfirstend-conncted to said closure means and having asecond emit-11mm from said first end; -a--1"1'rst"frangible diaphragm connected to said second 'end-of said tubular vessel so as to close said second vessel from said first vessel; a se'cond frangiblediaphragm located at an intermediate portion of said tubular second vessel so as to *divide it into two compartments one of which is enclosed by said first and second fran gible diaphragms and the-other of which is-enclosed by said closure means and said second diaphragm, whereby any liquid or powder contained in said first compartment is hermetically sealed against deterioration by said frangible diaphrag'ms; a sealed gas cartridge mounted in said other compartment; and means for opening said gas cartridge, whereby the pressure of the gasreleased by said cartridge upon the opening thereof will breaksaid second frangible diaphragm and-force any liquid or powder into-said one compartment against said first diaphragm so as to breaksaid first diaphragm and plunge the liquid or powder into any liquid contained in said first vessel and will force the mixture of the materials of said two 'vesselsout through said discharge port. v

THOMAS A. HENSHAW.

REFERENCES CITED The following references are of "record in the file-of this patent:

:UNITED STATES PATENTS Number Name Date 228,621 Folsom I June -8, 138!) 2,167,232 Boyd -July 2 5, 1939 2,381,606 Lee Aug. 17, 1945 2,452,309 "Leech et'al.- Oct. 26, 1948 

